骨桥蛋白通过内质网应激诱导C2C12肌细胞胰岛素抵抗  

Osteopontin-induced ER stress results in insulin resistance in C2C12 myocytes

作　　者：刘华[1] 陈昊[1] 唐照 张叶敏[2] 李明欣[2] 汪长华[2] 

机构地区：[1]连云港市第一人民医院病理科,江苏连云港222002 [2]武汉大学基础医学院病理生理学教研室,湖北武汉430071

出　　处：《中国病理生理杂志》2015年第6期1075-1080,共6页Chinese Journal of Pathophysiology

基　　金：国家自然科学基金资助项目(No.30770758/H0178)

摘　　要：目的:探讨骨桥蛋白(osteopontin,OPN)对C2C12肌细胞胰岛素抵抗的影响及其可能的机制。方法:低血清培养辅以胰岛素处理诱导C2C12成肌细胞分化为C2C12肌细胞,蛋白免疫印迹检测蛋白质的表达,离心法分离细胞膜,葡萄糖摄取试剂盒定量葡萄糖摄取。结果:(1)骨桥蛋白以剂量依赖和时间依赖方式抑制胰岛素刺激的蛋白激酶B(Akt)的磷酸化,并抑制胰岛素所致的葡萄糖转运体4(Glut4)膜位移和葡萄糖的摄取;而特异性的抗OPN受体CD44抗体预处理可逆转上述变化。(2)OPN可诱导C2C12肌细胞的内质网应激,并促进c-Jun氨基端激酶(JNK)的磷酸化。(3)内质网应激抑制剂4-苯基丁酸(4-PBA)可降低OPN所增加的JNK磷酸化,恢复胰岛素刺激所致的Glut4的膜位移以及葡萄糖摄取。结论:骨桥蛋白通过诱导C2C12肌细胞内质网应激导致胰岛素抵抗。本研究为揭示骨桥蛋白在胰岛素抵抗和糖尿病中的作用提供了新的实验依据和理论解释。AIM： To investigate the potential role of osteopontin（ OPN） in insulin resistance in C2C12 myocytes and its underlying mechanism. METHODS： C2C12 myoblasts were induced by low concentration of serum and insulin treatment to differentiate into myocytes. Western blot was performed to detect the protein abundance and phosphorylation using specific antibodies. Plasma membrane was isolated by centrifugation. Glucose uptake was measured by glucose uptake assay. RESULTS： OPN treatment suppressed insulin-stimulated protein kinase B（ Akt） phosphorylation in a dose- and time-dependent manner,accompanied with decreased membrane translocation of glucose transporter type 4（ Glut4） and reduced glucose uptake. Neutralization of OPN specific receptor in skeletal muscle with CD44 antibody mitigated OPN-induced inhibitory impact on insulin action. Furthermore,OPN treatment resulted in endoplasmic reticulum（ ER） stress and phosphorylation of c-Jun N-terminal kinase（ JNK）. Administration of ER stress inhibitor 4-phenylbutyrate（ 4-PBA） diminished the detrimental effects of OPN on JNK phosphorylation,Glut4 membrane translocation and glucose uptake. CONCLUSION： ER stress mediated OPN-induced insulin resistance in C2C12 myocytes.

关 键 词：骨桥蛋白 胰岛素抵抗 内质网应激 C2 C12肌细胞 

分 类 号：R363.2[医药卫生—病理学]